|Perl: the Markov chain saw|
modifying a string in placeby davidj (Priest)
|on Jan 19, 2006 at 18:11 UTC||Need Help??|
davidj has asked for the
wisdom of the Perl Monks concerning the following question:
My fellow monks,
I have an interesting text processing task before (Not homework). What I need to do is open a file, skip the first 4 lines, then on all the remaining lines, duplicate each character except for the '^' and '#' characters, and rewrite the file.
On an input file of:
the output should be:
I currently have the following code which works perfectly well:
I didn't like the idea of creating a temporary string, so I have the following which modifies the text as it is processing it, and also works perfectly well:
I don't like this solution because it breaks the cardinal rule of not modifying a for loop counter inside the loop. (Not that I'm any kind of coding purist, mind you :)
Benchmarking the solutions indicates that (not surprisingly) using a temporary string is quicker. The following results are on 250000 iterations of a file with 1750 lines, each line no more than 50 characters.
Now to my curiosity: Both of these solutions work and I am satisfied with using either of them. What I'd like to have, purely for the educational value, is a more "Perlish" way of doing this, and/or a more efficient way.
as always thank you for your assistance,